Secure digital traffic analysis

ABSTRACT

A network monitoring “sensor” is built on initial startup by checking the integrity of the bootstrap system and, if it passes, downloading information from which it builds the full system including an encrypted and an unencrypted portion. Later, the sensor sends hashes of files, configurations, and other local information to a data center, which compares the hashes to hashes of known-good versions. If they match, the data center returns information (e.g., a key) that the sensor can use to access the encrypted storage. If they don&#39;t, the data center returns information to help remediate the problem, a command to restore some or all of the sensor&#39;s programming and data, or a command to wipe the encrypted storage. The encrypted storage stores algorithms and other data for processing information captured from a network, plus the captured/processed data itself.

REFERENCE TO RELATED APPLICATION

This application claims priority to and is a nonprovisional of U.S.Provisional Application 62/055,043, filed Sep. 25, 2014, with title“Distributed Computer Security Platform.”

FIELD

The present invention relates to electric digital data processing. Morespecifically, the present invention relates to protecting data andmonitoring users, programs or devices to maintain the integrity ofplatforms.

BACKGROUND

In the arms race that is computer security, malware writers and computersecurity professionals are continuously working to improve theirtechniques for stealing information and protecting it, respectively. Anynetwork-connected computer might be vulnerable to attack from otherdevices on the network, so there is always a need for improved computersecurity techniques and devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a system implementing an embodiment ofthe inventive system.

FIG. 2 is a functional block diagram of a sensor in the embodiment ofFIG. 1.

FIG. 3 is a schematic diagram of a computing resource used in variousembodiments.

FIG. 4 is a flowchart of a boot-up sequence of a sensor for use in theembodiment of FIG. 1.

FIG. 5 is a flowchart of operation of a sensor for use in the embodimentof FIG. 1.

DESCRIPTION

For the purpose of promoting an understanding of the principles of thepresent invention, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will, nevertheless, be understood that nolimitation of the scope of the invention is thereby intended; anyalterations and further modifications of the described or illustratedembodiments, and any further applications of the principles of theinvention as illustrated therein are contemplated as would normallyoccur to one skilled in the art.

Generally, one form of the present system is a data network monitoringdevice (called a “sensor” in this description) that is physicallyinstalled with one or more taps on a data network, retrieves buildinformation from a secure source (such as an authenticated server, FTPserver at a known IP address, or other sufficiently authoritative sourcefor a particular implementation as will occur to those skilled in theart), and builds itself (i.e., prepares and/or installs its operationalcomponents) in situ using one or more file manipulation tools,compilers, automated parsing engines, or the like as will occur to thoseskilled in the art. Upon successfully booting post-build, the sensormounts an encrypted storage volume, monitors data traffic at the tap,stores observed data on the encrypted volume, analyzes observed data,and saves the analytics on the encrypted volume, too. The sensorgenerates alarms when appropriate, monitors its own “health” (securestate), recovers from attack, and implements a “self-destruct” functionthat can be triggered remotely. Suspicious traffic is run through avariety of filters and/or analyzed by human analysts. Each of thesecomponents, functions, and operations is discussed further herein.

With reference to FIG. 1, example system 100 includes a sensor 102connected via a tap to the connection between subnet 104 and a datacommunications network 106, such as the Internet. In this example,configuration server 108 is also connected to data network 106, as arecollection repository 110, data center 112, and analyst center 114, eachof which will be discussed in further detail. In other embodiments,configuration server 108, collection repository 110, data center 112,and analyst center 114 are combined in a single facility incommunication with data communications network 106. In still otherembodiments, configuration server 108, collection repository 110, datacenter 112, and analyst center 114 are situated in two or more locationson data communications network 106, such as different subnets. In thisembodiment, when sensor 102 is installed, it is physically connected sothat it has access to all traffic passing between subnet 104 and network106 using wired or wireless data capture. In alternative embodiments,sensor 102 is positioned as a bridge between networks, while in others,sensor 102 is connected to one particular network and monitorscommunications on that network as described herein.

The initial boot up process 300 for sensor 102 with reference to FIG. 3,with continuing reference to FIG. 1 and additional reference to theexemplary embodiment 200 of sensor 102 illustrated in FIG. 2, whensensor 102 is first powered up, bootstrap platform 202 (also known asthe “base system”) loads (302) an operating system, such as a custombuild of CentOS, from local memory. Of course, other operating systemssuch as other variants of Linux, Windows, QNX, iOS and Android can beused in other implementations as will occur to those skilled in the art.

Exemplary sensor 200 then obtains (304) an IP address for the one ormore network taps 204 from a DHCP server on subnet 104. In otherembodiments, the IP address for exemplary sensor 200 is preconfigured(e.g., fixed during a configuration process or at initial boot), whilein still others it is assigned using other techniques as will occur tothose skilled in the art. Sensor 200 then communicates withconfiguration server 108 using an automation tool such as Puppet (seehttp://puppetlabs.com/puppet/puppet-open-source). Of course, otherautomation and/or synchronization tools could be used as will occur tothose skilled in the art. Sensor 200 downloads (306) files andinstructions for building itself from the base system 202 into fullyoperational sensor 200, then executes (308) them. Intelligence,algorithms, signatures, and sensor profile data are pulled (310) fromconfiguration server 108 and stored in encrypted storage 206. When thebuild is complete, sensor 200 is rebooted (312) to begin monitoringtraffic received through network taps 204.

Normal operation (400) of sensor 200 will now be described withreference to FIG. 5 and continuing reference to FIGS. 1 and 2. Encryptedstorage 206 in the present embodiment comprises an encrypted drivepartition in sensor 200 that, as sensor 200 is booted (402), remainsunmounted and not visible to bootstrap platform 202 and other subsystemsoperating in sensor 200. During the boot process, validity checkprogramming of sensor 200 communicates (404) through automation toolswith data center 112 and requests instructions (406) whether (and, insome embodiments, how (e.g., instructions and/or cryptographic keymaterial or information from which sensor 200 can derive key material))to access encrypted storage 206 and continue booting and/or operating.For example, in some embodiments, unlocking code in base system 202and/or unlocking information downloaded from data center 112 orconfiguration server 108 may include decryption key information receivedfrom one of those remote systems and use (408) the key to accessencrypted storage 206. In “split-key” embodiments, sensor 200 storesinformation locally that the unlocking code must combine with otherunlocking information downloaded from one of the remote servers toproduce the key for accessing encrypted storage 206. In otherembodiments, when the system 202 wants to mount encrypted storage 206,the unlocking code has to retrieve at least part of the executable codefrom a remote source. In still other embodiments, access to encryptedstorage 206 is performed by the unlocking instructions as a function ofinformation retrieved from the remote source in other ways as will occurto those skilled in the art.

If sensor 200 does not receive that instruction, or for some reasonsensor 200 is unable to communicate with data center 112, sensor 200executes error-handling code (410), does not mount encrypted storage206, and remains a “base system” without customized features,intelligence, algorithms, and sensor data history. For example, ifsensor 200 were stolen and started up in a different location on theInternet—or completely disconnected from the Internet—this lockoutprevents the thief from getting information from encrypted storage 206or learning how the sensor 200 operates. In some embodiments, sensor 200then listens (412) for a “kill” command from data center 112 or analystcenter 114 and, if such a command is received, wipes (414) encryptedstorage 206 with government-grade wiping protocols and/or othertechniques as will occur to those skilled in the art. Even if the thiefwere to detect a missing mounted drive, if they attempted to mount thedrive, sensor 200 would self-destruct and execute the “kill” command.

The validity check programming of sensor 200 may take different forms indifferent embodiments, but generally determines whether the unencryptedstorage is in a secure state (that is, a state where, to an extentappropriate for the context, sensor 200 has collected enough informationto be sufficiently confident that its state is fully operational, nottampered with, not subject to virus or other malware activity, andneither intentionally or unintentionally corrupted). In someembodiments, the validity check programming sends data from sensor 200to data center 112 for analysis, while in others the validity checkprogramming creates hashes of files and other information, sending justthe hashes to data center 112. Other validity check techniques may beused as will occur to those skilled in the art. In various embodiments,validity check programming runs at boot time, on a periodic basis, atrandom times, when triggered by an action or attempt to take an action,upon receiving a (preferably authenticated) command, at other times, orat more than one of these times, as will occur to those skilled in theart.

In the present embodiment, each file stored in sensor 200′s non-volatilememory is hashed to create an identifying fingerprint of that file. Invarious embodiments, various components of the system 100 use hashfunctions SHA-1, SHA-256, MD-4, MD-5, RIPEMD, or another hash functionas will occur to those skilled in the art. The hash of the correctversion(s) of each file is stored in data center 112, and sensor 200periodically sends current hashes of its files back to data center 112,which compares those live hashes with the previously stored, correcthashes. In various embodiments, this process includes hashes of avariety of data elements, such as all files, user accounts, localpasswords, directory listings, software manifests, configurationoptions, or some combination thereof so that any changes an attackermight make are detected in this periodic self-check. In someembodiments, data center 112 maintains “known good” hashes of files andconfiguration data associated with each of a plurality of sensors, andwhen a particular sensor 200 contacts data center 112 to validate itsstate, sensor 200 includes information sufficient to determine itsidentity so that data center 112 can match the request with the correctset of file hashes, configuration data, etc. In various embodiments, theidentity information comprises a serial number for sensor 200, a serialnumber associated with a particular installation, a cryptographicsignature that authenticates a particular sensor 200, or otherinformation or technique as will occur to those skilled in the art. Ineach of these embodiments, data center 112 accepts the requests from theone or more sensors 200 by listening on one or more ports for datatransmissions that are parsed into the information needed to check thevalidity of the data from which the hash was made, though in otherembodiments the accepting and receipt of requests will take analogousforms as will occur to those skilled in the art.

If changes are detected, the system returns itself to its previous“correct” state by restoring a snapshot, downloading correct versions ofthe modified files and/or configurations (and overwriting the“incorrect” versions), and other steps that will occur to those skilledin the art. When these files and settings are restored, the attacker'saccess is typically removed along with any damage they have caused, andthe sensor 200 contacts data center 112 and/or analyst center 114 toreport the event.

In the illustrated embodiment of sensor 200, if data center 112 detectsthat sensor 200 has been compromised, system operators at analyst center114 can issue a kill command to the sensor 200. Upon receiving the killcommand, sensor 200 unmounts encrypted storage 206 and securely wipesthe associated storage space. In some embodiments, sensor 200automatically engages this “kill” process if it cannot reach data center112 to “check in” over a particular period of time.

When this illustrated embodiment of sensor 200 is operating, trafficcaptured (416) at taps 204 is allowed to pass between subnet 104 andnetwork 106 without degradation of service or speed, but a copy of thecaptured traffic is processed (418) by analysis engine 208 of sensor200. Analysis engine 208 (at certain times or under certain conditions,in some embodiments) records a full packet capture of the network datain encrypted storage 206, but also analyzes its content. For example,analysis engine 208 checks the traffic for specific types ofconnections, including, for example, those for HTTP, SSH, DNS, and thelike, and the connections requested and/or made in the traffic arecompared to the intelligence previously pulled from configuration server108. In various embodiments, analysis engine 208 compares the traffic topatterns and heuristics of known attacks, expected traffic andparticular risks associated with the given client (from a “clientprofile”), expected traffic in particular risks associated with theclient's industry (from an “industry profile”), and the like. Whenattacks are found, they are flagged, and one or more responses and/orremediation techniques may be implemented depending on the configurationof sensor 200. In various implementations, “flagging” takes the form ofstoring the relevant portion of data in encrypted storage 206, saving adata record describing the event in encrypted storage 206, informingdata center 112 about the event, alerting one or more individuals atanalyst center 114, and other actions as will occur to those skilled inthe art.

In addition, if an HTTP or other connection is known to be bad or issuspicious, either sensor 200 or data center 112 (after receiving theparameters and/or content of the connection from sensor 200) opens it ina sandbox 210 (illustrated here as part of sensor 200, though otherimplementations will occur to those skilled in the art) wherein allactions of the webpage are executed in a protected environment. Thatsandbox 210 is monitored for intelligence as to what thesuspicious/malicious content does, including without limitation networkresources that the content accesses, scripts it executes, directoriesand files it tries to access, applications it tries to open,configuration data it tries to change, and other activities as willoccur to those skilled in the art. If the sandbox 210 is local to sensor200, this intelligence is recorded in encrypted storage 206 andcommunicated (either at that time or at a later time) to collectionrepository 100.

Further, analysis engine 208 runs some or all of the captured contentthrough one or more signature-based comparison engines (such as Yara) tocompare the traffic with one or more threat databases (such asVirusTotal) in real time. Of course, alternative comparison engines,techniques, and databases will be used in alternative embodiments aswill occur to those skilled in the art.

When analysis engine 208 finds a match or detects suspicioustraffic/connection/content, any of a variety of actions are takendepending on the system configuration. For example, a malicious orsuspicious web link, image, script, executable file, or the like may berendered, interpreted, or executed in sandbox 210 local to sensor 200 orat data center 112. Sensor 200 or data center 112 may sendmeta-information about the traffic/connection/content, the contentitself, and/or telemetry regarding therendering/interpretation/execution to collection repository 110. Sensor200 or data center 112 may also automatically notify one or moreadministrators of system 100, as well as representatives and technicalpersonnel responsible more directly for administration of subnet 104.Sensor 200 or data center 112 may also notify one or more human analystsat analyst center 114 and give them information about the situation sothey can subject it to further analysis. The human analysts viewinformation about the traffic/connection/content on computing devices inanalyst center 114 and perform additional analysis of—and directremediation in response to—the incident.

In various embodiments, taps 204 capture traffic between subnet 104 andnetwork 106 as described above, but operate independently of sensor 102.In such embodiments, taps 204 may be internal or external to sensor 102,but enable data to pass between subnet 104 and network 106 even whensensor 102 is powered down.

In some embodiments of the system described herein, the computingresources/devices that are applied generally take the form of a mobile,laptop, desktop, or server-type computer, as mentioned above and as willoccur to those skilled in the art. The “computer” 300, as this examplewill generically be referred to with reference to FIG. 3, includes aprocessor 320 in communication with a memory 330, input interface(s)340, output interface(s) 350, and network interface 360. Memory 330stores a variety of data, but is also encoded with programminginstructions executable to perform the functions described herein.Power, ground, clock, and other signals and circuitry (not shown) areused as appropriate as will be understood and easily implemented bythose skilled in the art.

The network interface 360 connects the computer 300 to a data network370 for communication of data between the computer 300 and other devicesattached to the network 370. Input interface(s) 340 manage communicationbetween the processor 320 and one or more touch screens, sensors,push-buttons, UARTs, IR and/or RF receivers or transceivers, decoders,or other devices, as well as traditional keyboard and mouse devices.Output interface(s) 350 provide a video signal to a display 380, and mayprovide signals to one or more additional output devices such as LEDs,LCDs, or audio output devices, local multimedia devices, localnotification devices, or a combination of these and other output devicesand techniques as will occur to those skilled in the art.

The processor 320 in some embodiments is a microcontroller or generalpurpose microprocessor that reads its program from the memory 330. Theprocessor 320 may be comprised of one or more components configured as asingle unit. Alternatively, when of a multi-component form, theprocessor may have one or more components located remotely relative tothe others. One or more components of the processor may be of theelectronic variety including digital circuitry, analog circuitry, orboth. In some embodiments, the processor is of a conventional,integrated circuit microprocessor arrangement, such as one or more COREi3, i5, or i7 processors from INTEL Corporation of 2200 Mission CollegeBoulevard, Santa Clara, Calif. 95052, USA, or OPTERON or PHENOMprocessors from Advanced Micro Devices, One AMD Place, Sunnyvale, Calif.94088, USA. In alternative embodiments, one or more reduced instructionset computer (RISC) processors, application-specific integrated circuits(ASICs), general-purpose microprocessors, programmable logic arrays, orother devices may be used alone or in combinations as will occur tothose skilled in the art.

Likewise, the memory 330 in various embodiments includes one or moretypes such as solid-state electronic memory, magnetic memory, or opticalmemory, just to name a few. By way of non-limiting example, the memory330 can include solid-state electronic Random Access Memory (RAM),Sequentially Accessible Memory (SAM) (such as the First-In, First-Out(FIFO) variety or the Last-In First-Out (LIFO) variety), ProgrammableRead-Only Memory (PROM), Electrically Programmable Read-Only Memory(EPROM), or Electrically Erasable Programmable Read-Only Memory(EEPROM); an optical disc memory (such as a recordable, rewritable, orread-only DVD or CD-ROM); a magnetically encoded hard drive, floppydisk, tape, or cartridge medium; a solid-state or hybrid drive; or aplurality and/or combination of these memory types. Also, the memory invarious embodiments is volatile, nonvolatile, or a hybrid combination ofvolatile and nonvolatile varieties.

Computer programs implementing the methods described herein willcommonly be stored and/or distributed either on a physical distributionmedium such as CD-ROM, or via a network distribution medium such as aninternet protocol or token ring network, using other media, or throughsome combination of such distribution media. From there, they will oftenbe copied to a hard disk, non-volatile memory, or a similar intermediatestorage medium. When the programs are to be run, they are loaded eitherfrom their distribution medium or their intermediate storage medium intothe execution memory of the computer, configuring the computer to act inaccordance with the method described herein. All of these operations arewell known to those skilled in the art of computer systems.

Each sensor 200 calculates bandwidth on each monitored link bycalculating the aggregate bandwidth over a particular (e.g., 4000 ms)time frame, pulls load on the link, and displays that to the customer.Bandwidth is factored into evaluations of the overall threat landscapeby allowing an analyst to compare it with the additional logs pulled viaother sensor operations. The net usage software of sensor 200 alsochecks to verify that sensor operations are functioning, e.g., anomaly,heuristic, and signature detection tools.

As files are downloaded across the network 106 and are verified by thesensor 200:

-   -   1. The sensor 200 begins to create file hashes for every known        file.    -   2. The sensor 200 matches the files to an intelligence list of        known bad or malicious files.    -   3. Sensor 200 runs all files against a “known good” file list to        determine whether the file is safe. A white list of files is        derived from previous analysis of all files on a network, e.g.,        driver files, applications, documents, etc. Analysts pull this        from network flow and put it into a repository where the file is        tagged and classified for comparisons on the sensor.

In some variations of the disclosed systems, additional data capturedfrom the network is correlated with stored intelligence for otherpurposes. In some of these embodiments, a client-side application runson an endpoint device (not shown) on a protected subnet (such as subnet104 shown in FIG. 1) verifying attacks against that device throughsignature-based detection. The client also has a client-side firewall,host-based intrusion detection, host-based intrusion prevention, contentfiltering, attack logging and optional full-disk encryption. The clientcommunicates captured information back to data center 112 for additionaland/or new threat signatures as well as reporting any active or detectedthreats. Signatures at data center 112 are derived from both logging onthe endpoint device as well as any threat information derived from thenetwork detection described elsewhere herein. In embodiments where aservice provider serves a plurality of endpoint devices and sensors,signatures from global intelligence and other threat detection locationsthat the service provider might have a relationship with are sent to theendpoint devices. In some of these embodiments, all threat data from theendpoints is correlated with threat data detected on the customernetwork as well as with overall threat data and network compromisesacross every customer the service provider has to give full visibilityinto minute attacks and threat vectors. Threat information is madeavailable to the service provider's customers through a customer portal.If threats are detected, the service provider provides full remediationto the affected customer.

With a standard security information and event management (SIEM)solution, the data cannot be fully trusted as an attacker could modifythe logging capability of the sending device and thus limit thevisibility that the SIEM solution has. In some embodiments, a device isplaced on a client network that collects logs from other devices on theclient network, and a separate device or service provider correlatesthat data with fully trusted network-collected data and verifiedendpoint-collected data to verify the validity and notice anomalies inthe SIEM data. This allows the system to add higher fidelity to the SIEMdata and notice when abnormalities appear in the collected information.

In some embodiments, outbound DNS on some client networks (such assubnet 104 in FIG. 1) can be pointed to a service provider's externalDNS servers, thereby allowing for active blocking of selected outboundtraffic based on DNS hostnames. In some of these embodiments, theservice provider blocks explicit sites as well as known threat sites andlocations for which customer traffic is bound. Analysts at analystcenter 114 can add blocks in real time as undesirable content is foundon its various customers' networks through network detectioncapabilities in the various elements of the disclosed system.

In still other embodiments, a service provider provides activevulnerability monitoring to a customer network both externally andinternally, and then correlates that data to what is found inside acustomer network from detection. This allows for a more proactiveclosing of vulnerabilities found in vulnerability scans. With someexisting systems, when a scan is completed the customer is provided witha list of high-, medium-, and low-level vulnerabilities that were found.When that happens, the user or company will focus on closing orremediating the high-level vulnerabilities first, then the medium levelones, then the low-level ones. Attackers know this and will sometimesalter their attacks to compromise low- to medium-level threat attacks,which customers take longer to close. By correlating vulnerability scandata with network-detected threat data, host, and endpoint data, somesystems implemented the present invention can assist companies in betterprioritizing which threats to close and remediate first.

The term “computer-readable medium” herein encompasses non-transitorydistribution media, intermediate storage media, execution memory of acomputer, and any other medium or device capable of storing a computerprogram implementing a method for later reading by a computer.

When an act is described herein as occurring “as a function of” aparticular thing, the system is configured so that the act is performedin different ways depending on one or more characteristics of the thing.

While the embodiments described above refer to hashes of files,configuration data, and other data, some embodiments replace each suchinstance with different kinds of characterization information thatcharacterizes the data as will occur to those skilled in the art. Forexample, the characterization information might only include specificportions of a file, an encoding of certain configuration settings, orprocessed portions of user profiles, among other options that will occurto those skilled in the art in view of this disclosure.

The various communications referred to herein may be sent and receivedsynchronously or asynchronously, using one- or two-way channels. Someembodiments will use the TCP/IP protocols, while other will use UDP overIP, and still others will use different techniques as will occur tothose skilled in the art in view of this disclosure.

All publications, prior applications, and other documents cited hereinare hereby incorporated by reference in their entirety as if each hadbeen individually incorporated by reference and fully set forth. Whilethe invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. A base system for a data network monitoringsystem, the base system comprising a processor, a network interface, anda memory, the memory being encoded with data and programming that isexecutable by the processor to: provide an operating system for the basesystem; retrieve build information from a secure source via the networkinterface; use the build information to set up operational components,the operational components comprising: validity check programming;encrypted storage access control programming; and error-handlingprogramming; execute the validity check programming; if the validitycheck programming reveals a correct state, then using the encryptedstorage access control programming, access a first portion of the memoryas encrypted storage, leaving a second portion of the memory asunencrypted storage; and capture data at the network interface andprocess the captured data as a function of information in the encryptedstorage; and if the validity check programming reveals an incorrectstate, executing the error-handling programming.
 2. The system of claim1, wherein the encrypted storage contains information usable by theprocessor to implement one or more algorithms for processing datacaptured at the network interface.
 3. The system of claim 1, wherein theencrypted storage contains at least a portion of the data captured atthe network interface.
 4. The system of claim 1, wherein the encryptedstorage contains information usable by the processor to implement one ormore functions that are not implemented in programming stored in theunencrypted storage.
 5. The system of claim 1, wherein programmingstored in the unencrypted storage is executable by the processor at boottime to: initially avoid accessing the encrypted storage; communicatewith a remote computer via the network interface; receive unlockinginstructions from the remote computer; and use the unlockinginstructions to access the encrypted storage.
 6. The system of claim 5,wherein the unlocking instructions comprise information including keymaterial usable for decrypting the encrypted storage.
 7. The system ofclaim 5, wherein the communicating with the remote computer comprisessending one or more hashes of information stored in the unencryptedstorage to the remote computer for validation.
 8. The system of claim 7,wherein the hashes include hashes of three or more source items selectedfrom the source item collection consisting of: files in the unencryptedstorage, one or more user accounts, local passwords, listings ofdirectories in the unencrypted storage, a software manifest, andconfiguration options for one or more software subsystems.
 9. The systemof claim 5, wherein the programming stored in the unencrypted storage isfurther executable by the processor to determine whether the unencryptedstorage is in a secure state; and if the unencrypted storage is not in avalid state, put the unencrypted storage into a secure state.
 10. Thesystem of claim 1, wherein processing the captured data comprisesstoring at least a portion of the captured data in the encryptedstorage.
 11. A data center for use in a secure network monitor system,the data center comprising a processor, a network interface, and amemory encoded with verification data and programming instructionsexecutable by the processor to: accept request data from a remotecomputer via the network interface, where the request data containscharacterization information that characterizes data stored at theremote computer; as a function of a comparison of the characterizationinformation with the verification data, either send a response to theremote computer that contains cryptographic key material or sendresponse data to the remote computer, where the response data contains arestore instruction.
 12. The data center of claim 11, wherein: thecharacterization information comprises hashes of a set of data elementsstored at the remote computer; and the verification data compriseshashes of known-good versions of the set of data elements.
 13. The datacenter of claim 11, wherein the response that contains the restoreinstruction further comprises data usable by the remote computer to putitself into a secure state.
 14. The data center of claim 11, wherein thecryptographic key material enables access to an encrypted memoryassociated with the remote computer.
 15. The data center of claim 11,wherein: the verification data comprises information corresponding toeach of a plurality of remote computers; the request includes identityinformation for the particular remote computer that sent the request;and the comparison operates on the verification data that corresponds tothe particular remote computer.
 16. A network monitoring systemcomprising a processor, a network interface, and a memory have anencrypted portion and an unencrypted portion, the unencrypted portionbeing encoded with programming instructions executable by the processorto: create one or more hashes of at least some of the information storedin the unencrypted portion of the memory; send the one or more hashes toa remote computer; receive a response from the remote computer; and ifthe response is of a first type, then use information in the response todecrypt the encrypted portion of the memory; and use information in theencrypted portion of the memory to capture and process data using thenetwork interface.
 17. The network monitoring system of claim 16,wherein the programming instructions are further executable by theprocessor to, if the response is of the second type, erase the encryptedportion of the memory.
 18. The network monitoring system of claim 16,wherein the programming instructions are further executable by theprocessor to flag dangerous content using filtering information in theencrypted portion of the memory.
 19. The network monitoring system ofclaim 18, wherein the filtering information used to flag dangerouscontent comprises at least one profile selected from the profile setconsisting of: a client profile comprising information thatcharacterizes at least one of expected content and unexpected contentfor a user of the network monitoring system; and an industry profilecomprising information that characterizes at least one of expectedcontent and unexpected content for any generic user who operates in aparticular industry, where the user of the network monitoring systemoperates in the particular industry.
 20. The network monitoring systemof claim 18, wherein the programming instructions are further executableby the processor to: open flagged content in a sandbox; collectintelligence regarding behavior of the flagged content as it is openedin the sandbox; and store the intelligence in the encrypted portion ofthe memory.